Initially, I had my application servers using the slave for short, read only queries, but this turned out to be highly unstable. The slave would start refusing connections, and the logs would fill with:
ERROR: canceling statement due to conflict with recovery
But then I starting getting these: DETAIL: User transaction caused buffer deadlock with recovery.
Read requests come in at anywhere between 200 and 1000/second.
I was wondering if there is some combination of configuration settings that would safely let me use the slave for read only queries?
Have you tried setting max_standby_archive|streaming_delay to several minutes (or whatever makes sense for your typical query durations), rather than disabling those settings with -1?